Increasing 'Jellification' of Canada's Lakes Worries Experts

No, Canadian lakes aren't going to start looking like big bowls of JELL-O, but they are becoming the homes of a stunning number of jelly-coated organisms that compete with plankton for food and other resources. That's alarming news for researchers, who worry that this imbalance is putting vital ecosystems in trouble.

The jelly-clad Holopedium is a small and unassuming organism that traditionally competes with many plankton species to feed on algae in lake waters. However, while plankton like the Daphnia water flea are integral members of aquatic food chains, the Holopedium is more like an ecological parasite, passing fewer nutrients to fish stocks that normally rely on plankton to survive.

Unfortunately, according to  a study recently published in the journal Proceedings of the Royal Society B, plankton populations in eastern Canadian lakes have been on the decline for the last several decades while Holopedium populations have been exploding to fill this ecological gap.

The cause, researchers say, is industry, whose historic acid deposits have greatly reduced calcium levels in the water. This, in turn, adversely affects calcium-rich plankton such as Daphnia, leaving the rival jellies - which don't require high calcium concentration - to thrive. (Scroll to read on...)

"As calcium declines, the increasing concentrations of jelly in the middle of these lakes will reduce energy and nutrient transport right across the food chain, and will likely impede the withdrawal of lake water for residential, municipal and industrial uses," study co-author Andrew Tanentzap, from the University of Cambridge, warned in a recent statement. "In Ontario, 20 percent of government-monitored drinking water systems now come from landscapes containing lakes with depleted calcium concentrations that favor Holopedium, and this is only set to increase."

So why is calcium so important? The researchers found that lower calcium levels means weaker calcified exoskeletons for the water flea plankton. That leaves them more vulnerable to predators since they have to dedicate more energy towards skeleton development.

Meanwhile, the Holopedium is left to freely feed without competition, exploding in population.

"It may take thousands of years to return to historic lake water calcium concentrations solely from natural weathering of surrounding watersheds," Tanentzap added. "We many have pushed these lakes into an entirely new ecological state."